It is estimated that the soils of approximately 2.5 million sites in the European Union are potentially contaminated and at least 14% of them require soil decontamination as a result of mining, industrial and urban activities. At the moment, only a small part of these sites have been remediated, leaving about 300,000 contaminated sites in need of remediation in the EU.

Although mining activities are important sources of soil contamination in some EU countries, metal industries are the most frequently reported to be important sources of contamination (representing 13% of total contaminated soils). Most frequent contaminants are mineral oils and heavy metals.

Contaminated sites don’t come without cost, both for the private sector and for public administrations. Clean-up of contaminated soils is a cost-intensive and technically complex procedure. According to data from the Superfund programme, US spends between 300 and 700$ million annually in soils remediation. In the EU, it is estimated that an average of 1€ per million euros of national GDP are spent on the management and remediation of contaminated sites, most of it coming from public budgets.

Directive 2006/21/EC regulates in the EU the management of waste from extractive industries in order to control major-accident hazards and to enable the production of the best available techniques (BAT) to manage mine sites whenever they are depleted, degraded or abandoned. This regulation calls for rehabilitation of these degraded areas, understanding rehabilitation as the proper treatment of the land affected in such a way as to restore the land to a satisfactory state, with particular regard to soil quality, wildlife, natural habitats, freshwater systems, landscape and appropriate beneficial uses.

The EU Directive affects an estimated area of 40,100 km², corresponding to land currently impacted by active mining. If compared with other continental areas, contaminated soils in Europe are well below other regions, which may reflect the high degree of regulation and monitoring of mining operations in the EU and the general trend of reducing mining activities over the past decades.

Globally, the extent of land area impacted by mining and quarrying is debated, but recent estimates range between 300,000 and 800,000 km². It’s a fact that mining is expanding in response to increasing societal demands for energy minerals, metals, and other construction and industrial minerals. Since the 1970s, extraction of metals has increased by more than 75%, non-metallic industrial minerals by 53% and construction materials by 106%. The main challenge ahead will be to resolve the inherent conflict between the growing impacts of increased demand for mineral resources essential for the energy transition and the need to protect and restore environmental goods and services.

Understanding the economics of contaminated land management is key to increase awareness and promote sustainable solutions. Annually, the loss of ecosystem services due to land degradation represents a reduction of 10-17% of global GDP. The stabilisation and restoration of contaminated soils typically require long-term efforts focused not only on local site conditions but also on adjacent waste-disposal sites, neighbouring areas affected by water pollution, distant areas affected by dust emissions and infrastructure (e.g. roads and railways).

Current EU initiatives for the development of new technologies and methods aim at removing or neutralising contaminants from the site so that the land can begin a non-mining, non-industrial activity while keeping alive the local economy and enhancing social acceptance and sustainability. In next posts, we will dig deeper into these remediation techniques.

Header image: Map of active metal and energy minerals mining sites. Source: SNL Metals & Mining Database, 2017.